Treatment of hydrocarbons



G. EGLOFF TREATMENT oF HYDRocARBoNs Filed April 22. 1940 7, aff

May 18, 1943 qu@ Nw .w no

Patented May 18, 1943 TREATMENT F HYDROCARBONS Gustav Egloff, Chicago, Il1;, assignor to Universal Oil Products Company, Chicago, Ill., a corporation of Delaware Application April 22, 1940, Serial N0. 330,945

claims.

This invention relates to the treatment of hydrocarbons for the conversion thereof into lower boiling hydrocarbons suitable for use as motor fuel, and particularly to the production of individual low `boiling hydrocarbons of an iso character which can be used as the base material in synthetic processes or directly as high antiknock constituents of motor fuel blends.

The invention is 'more speciflcally concerned with the use of metal halide catalysts 'and particular process flows for accomplishing the objects mentioned.

It has been recognized for some time that there is a distinct limitation bothas to quality and yield of 4product in strictly thermal cracking processes aimed at the production .of optimum yields of high antiknock value gasoline. Even though crackingk plants have been developed which are more or less perfect mechanically and wherein individual fractions of hydrocarbon charges and intermediate insufliciently converted conversion products are subjectedindividually to sets of conditions best suited to'their effective conversion, it has been found that high antiknock value materials useful as motor, fuel are diilicult to obtain without sacrifice of yields and increased losses due to formation of fixed gases on the one hand and heavy carbonaceous residual materials on the other.v To overcome these limitations, a wide variety of catalytic materials have been examined with varying degrees of success. The present process is anv improvement over ordinary thermal and catalytic cracking processes in the combination of particularly effective catalysts and a process ow which is adapted to produce increased yields of low boiling products, particularly those of an isoparafilnic character which have high antiknock value.l y g In one specific embodiment the present invention comprises fractionating a hydrocarbon oil along with products of catalytic cracking to produce a relatively lightand a relatively heavy reflux material, separately converting these light and heavy reiluxes in the' presence of metal halide catalysts, passing the products from these conversions to a reaction zone in which time is given for the -completion of the desired conversion reactions, passing the conversion products thereafter to a separation zone preferably operated under reduced pressure wherein heavy reaction products are separated from normally vaporous 'materials and fractionating said vaporous materials to produce a plurality of individual hydrocarbon fractions and the light and heavy refluxes mentioned.

The features and advantages of thepresent invention will be further evident from a consideration of the following description of a characteristic operation in connection with the attached drawing which shows diagrammatically in general side elevation and without regard to exact proportioning of interconnected units an arrangementof apparatus in which the process of the invention may be carried out. "Ihe .plant is not represented in the drawing in complete detail, since the drawing has been simplified to assist in thedescription of the flow. and to bring out the more salient features of the process.

from the primary distillation of a crude oil is introduced to a plant by way of a line I containing a valve 2 and into a charging pump 3 which discharges either through line 4 containing valve 5 into a point in the nal fractionating zone 6 or directly to a heatingelement I5 by way of branch discharge line I3 containing valve I4, heater I5 being arranged to receive heat from a furnace I6. Whether the charging stock is-int-roduced directly to a conversion zone or into a fractionating zone will depend upon the characteristics of the stock and both methods of introduction are comprised within the scope of the invention as may be expedient. When introducedv g l products are withdrawn from fractionating zone 6 by way of a line 'l containing valve 8 to a pump 9 which discharges through aline II containing" valve I2 and leading to, line I3 containingwhat` ever portion of the charging stock is to be fed directly toprimary heating "element I5. Light reux condensate is removed from a cooling plate 21 by way of line 28 containing a valve 29 to a pump 3U which discharges through line 3| containing valve 32 to a secondary heating element 33 arranged to receive heat from a furnace 34. It will thus be seen that a charging stock may be converted in admixture with heavy reflux condensates while the 4light reflux condensate is separately converted.

In accordance' with the present pnocess light and heavy reflux condensates from the fractionatign of the cracked products and the charging stock are separately catalytically cracked in the presence of metal halide catalysts, particularly aluminum chloride and similarly acting materials. These catalysts are preferably introduced in a finely divided and substantially anhydrous condition in suspension in oils at moderate temperatures although they may be injected as vapors wherever feasible as in the case of aluminum chloride. As indicated in the drawing, line 31 containing valve 38 and leading to catalyst pump 39 is provided for the admission of the catalytic material, the pump discharging partially through line 40 containing valve 4I to primary heating element and conversion zone I while' the re- -mainingportion of the catalyst is directed through line 42 containing valve 43 to secondary heating element 33. Conditions of temperature and pressure, amount of catalyst and size of the two individual heaters will be determined by the characteristics of the charging stock., However, as a rule more moderate conditions will be employed in the conversion of the mixture of heavy reflux and charging stock while more severe conditions are employed in the conversion of the light reilux. Temperatures of from 450-750 F. may be employed at the exit of the two heating elements and superatmospheric pressures up to 500'lbs. per square inch, the conditions of each coil being preferably regulated to produce maxif mum yields of low boiling iso-parafil-nic hydrocarbons. `Hydrogen halides. such as hydrogen chloride may be admitted at any point inthe conversion zones to assist in promoting the primarily desired production of iso-paraflins.

The partially converted products and catalyst from primary heating element I5 pass through line I 'I containing valve I81while similar products pass from secondary heating element 33 through line containing valve 36, both sets of products passing to a reaction chamber I9 which is provided to permit continued conversion of the products to a desired point. The total products from reaction chamber I9 pass through line 2l) containing valve 2| to a separator 22 which preferably operates under a pressure lower than that employed in the preceding reaction chamber. In this separator, aluminum chloride or other metal halide sludges and heavy residual reaction products drop out and are removed through line 23 containing valve 24 while the vapors from the stead of the upper set 'of collecting plates 46, 49,

52, 55, 58, and 6 I there may be used a corresponding number of separate fractionating 'columns which act successively to fractionate the vapors evolved above collecting plate 21. By the choice of fractionators of suitable design and capacity, it is preferred to separate by way of line 44 containing valve 45 a light iixed gaseous fraction comprising essentially hydrocarbons of three, two and `one carbon atoms and hydrogen, which are removed and used in any desired manner such as, for example, fuel inthe furnaces of the procl Line 56 containing valve 5i is shown in the drawingas removing a normal butane frac-tion which may be further treated by isomerization or dehydrogenation processes to -produce more reactive compounds useful in the synthesis of high antiknock value hydrocarbons.

' Line 53 containing valve 54 is indicated as a means of removing an iso-pentane fraction which is utilizable directly as a high antiknock constituent of motor fuel or which may be alkylated readily as in the case of iso-butane to form high boiling iso-paraiin hydrocarbons which may be used as ingredients of the so-called safety fuels.

Line 56 containing valve 51 permits the recovery of a normal pentane fraction which may be utilized by methods similar to those suggested for the utilization of normal butane.

Line 59 containing valve 60 permits the removal of a mixture of iso-hexanes which are utilizable directly in ordinary motor fuel or in aviation fuels.

Line 62 containing valve 63 permits the withdrawal of a normal hexanefraction which may be separately utilized in the production of othei hydrocarbons of good antiknock value.

The following example is introduced to indicate in a general way the types and yields of productsl normally obtainable in the `operation of the present process although the scope of the invention is not to be considered as limited by the character of the specific data introduced.

The charging stock to the process may be a Mid-Continent gas oil having an A. P, I. gravity of 30, which is introduced to a fractionating zone in the manner described in the process ow. By operating a primary conversion element at a temperature of approximately 500 F. and a secondary heating element at a temperature of 600 F. utilizing pressures of lbs. per` square inch at the exit of the heating elements and in the succeeding reaction chamber, approximately 5% by weight of aluminum chloride being suspended in the fractions undergoing conversion in each v zone. The final 'weight per centV yield of products may be as follows:

Per cent Gases lighter than butanes 15 Iso-butane 25 Normal butane 5 Iso-pentane 20 Normal pentane 5 Iso-hexanes 15 Normal hexane fraction and heavier 15 gether with additional metal halide catalyst, tov

independently controlled higher conversion temperature in asecond heating zone, introducing the reaction products including the suspended catalysts from both said zones into a reaction zone maintained under catalytic conversion con- `clitions and therein continuing conversion, separating the commingled products into vapors and residue, fractionatng the. vapor to separate a plurality offfractions therefrom, including a relatively heavy reflux condensate and a lighter reux condensate,l and returning the heavy reflux condensate to the first-mentioned heating zone and the lighter reflux condensate to said second heating zone.

2. The process of claim 1 further characterized in thatl said metal halide comprises aluminum chloride.

; 3. The process of claim 1 further characterized ing a lighter oil,l together with additional metal 10 halide catalyst and hydrogen halide, to independently controlledl conversion temperature in a .second heating zone,` introducing the reaction products including the suspended catalysts from both said zones into a reaction zone maintained 15v under catalytic conversion conditions and therein continuing conversion, separating the commm- Sled products into vapors and residue, fractionatine the vapors to separate a plurality-of frac- Y tions therefrom, including a relatively heavy reux condensate and a lighter-reflux condensate.

. and returning the heavy reflux condensate to the first-mentioned heating zone and the; lighter renux condensate to said secondheating z'one. 4

5. The process of claim 4 further characterized 'in that the metal halide catalyst comprises alumi- V 1 num chloride andv thefhydrogen halide comprises hydrogen chloride.

lGUS'IAV EGIQFF. 

